Command Line Option

This article describes built-in commands and its options

fluentd

Invoke fluentd. Here is supported options:

Usage: fluentd [options]
-s, --setup [DIR=/etc/fluent] install sample configuration file to the directory`
-c, --config PATH config file path (default: /etc/fluent/fluent.conf)
--dry-run Check fluentd setup is correct or not
-p, --plugin DIR add plugin directory
-I PATH add library path
-r NAME load library
-d, --daemon PIDFILE daemonize fluent process
--no-supervisor run without fluent supervisor
--user USER change user
--group GROUP change group
-o, --log PATH log file path
-i CONFIG_STRING, inline config which is appended to the config file on-fly
--inline-config
--emit-error-log-interval SECONDS
suppress interval seconds of emit error logs
--suppress-repeated-stacktrace [VALUE]
suppress repeated stacktrace
--without-source invoke a fluentd without input plugins
--use-v1-config Use v1 configuration format (default)
--use-v0-config Use v0 configuration format
-v, --verbose increase verbose level (-v: debug, -vv: trace)
-q, --quiet decrease verbose level (-q: warn, -qq: error)
--suppress-config-dump suppress config dumping when fluentd starts
-g, --gemfile GEMFILE Gemfile path
-G, --gem-path GEM_INSTALL_PATH Gemfile install path (default: $(dirname $gemfile)/vendor/bundle)

Important options

--suppress-config-dump

Fluentd starts without configuration dump. If you don't want to show configuration in fluentd logs, e.g. don't show private keys, this options is useful.

--suppress-repeated-stacktrace

If set true, suppress stacktrace in fluentd logs. Since v0.12, this option is true by default.

--without-source

Fluentd starts without input plugins. This option is useful for flushing buffers with no new incoming events.

-i, --inline-config

If you use fluentd on XaaS which doesn't support persistent disks, this option is useful.

--no-supervisor

If you want to use your supervisor tools, this option avoids double supervisor.

Set via configuration file

Several options could be set via <system> directive configuration file. See configuration file article.

fluent-cat

Send event to fluentd's in_forward/in_unix plugin. This is useful for testing.

Usage: fluent-cat [options] <tag>
-p, --port PORT fluent tcp port (default: 24224)
-h, --host HOST fluent host (default: 127.0.0.1)
-u, --unix use unix socket instead of tcp
-s, --socket PATH unix socket path (default: /var/run/fluent/fluent.sock)
-f, --format FORMAT input format (default: json)
--json same as: -f json
--msgpack same as: -f msgpack
--none same as: -f none
--message-key KEY key field for none format (default: message)

example

Send json message with debug.log tag to local fluentd:

% echo '{"message":"hello"}' | fluent-cat debug.log

Send to other machine:

% echo '{"message":"hello"}' | fluent-cat debug.log --host testserver --port 24225

If this article is incorrect or outdated, or omits critical information, please let us know. Fluentd is a open source project under Cloud Native Computing Foundation (CNCF). All components are available under the Apache 2 License.